It is already known to provide first and second connection terminals for a vehicular radio receiver, the second terminal serving for continuous furnishing of electric power to the circuits of the receiver for storing announcement data and/or coding for an alarm system to counteract vehicle theft, while the other reception portions and the audio reproducing portions of the vehicular radio connected to the first terminal can be switched off by the ignition switch of the motor vehicle.
It is known from German Patent 29 10 073C2 to provide an automobile broadcast radio receiver with a traffic announcement decoder, with announcement recognition and with automatically controlled recording and reproduction stages, whereby a digital memory is provided for recording the traffic announcements. In that known system the receiver, traffic radio decoder and memory are continuously switched on.
An energy saving circuit is known from U.S. Pat. No. 5,301,510, which connects the power supply only to the stages necessary for evaluation of the traffic announcements, but only until there is a need for reception and reproduction of a broadcast transmission. This known energy saving circuit loads the vehicle battery even when there is no need to reproduce an audio broadcast and the auto-radio is accordingly switched off.